1. Field of the Invention
The present invention relates to a light-emitting device, and more particularly to an improvement on a light-emitting device in which a plurality of light-emitting semiconductor devices are mounted.
2. Description of the Related Art
There has been known a light-emitting device in which a red light-emitting semiconductor device that emits red-base light, a green light-emitting semiconductor device that emits green-base light and a blue light-emitting semiconductor device which emits blue-base light are assembled into a single package so as to emit light of an arbitrary color.
In packages, with a view to simplifying wiring, it is preferable to commonize a wiring pattern on a cathode side or an anode side of a package. For example, when communizing a wiring pattern on the cathode side, a cathode common pad or electrode is provided on the package, so that cathode electrodes of the semiconductor devices are connected to this cathode common electrode. On the other hand, three electrically independent anode electrodes are provided on the package so as to be connected individually with anode electrodes of the semiconductor devices.
Whether to commonize cathode electrodes or anode electrodes of a plurality of light-emitting semiconductor devices is arbitrarily selected depending upon the application, purpose and the like of a light-emitting device.
There are various forms in which a cathode and an anode are disposed in a light-emitting semiconductor, and for example, in a red light-emitting semiconductor, an anode and a cathode are sometimes formed on different planes. A light-emitting semiconductor device like this constitutes a vertically energized chip. On the other hand, in a blue light-emitting semiconductor device which is made of a III group nitride system compound semiconductor device, an anode and a cathode are formed on the same plane.
These light-emitting semiconductor devices are selected as required to be mounded on a package, and as this occurs, the type of the package (cathode commonized or anode commonized) needs to be studied as a selection criterion.
From the viewpoint of commonization in parts, Patent Document No. 1 proposes a package that can be used as a cathode commonized type or an anode commonized type.
In addition, Patent Document No. 2 and Patent Document No. 3 also disclose techniques associated with this patent application by reference.
Patent Document No. 1:JP-A-9-321341Patent Document No. 2:JP-A-2001-127343Patent Document No. 3:JP-A-2001-143516
According to the technique disclosed in Patent Document No. 1, the single package can be used as the cathode commonized type or the anode commonized type.
However, a wire bonding pattern differs between a light-emitting device in which cathodes are commonized and a light-emitting device in which anodes are commonized. Because of this, although the package can be commonized, when manufacturing a light-emitting device, a manufacturing process differs between the cathode commonized type light-emitting device and the anode commonized type light-emitting device.
Then, the inventor and others have made every possible effort to realize a further commonization of parts of a light-emitting device, as well as a commonized manufacturing process that can be used to manufacture a light-emitting device, whether it is of the cathode commonized type or the anode commonized type.